I was able to modify a used pipe and install a narrow band Oxygen Sensor this weekend. I chose to mount the Sensor close to the head as that is where they are located on my wife's Honda and on my Vibe. It is in plain sight - but this is a temporary pipe to be used only while I am getting the jetting sorted out. I have only ridden up to the gas station and back, and this is what I have found so far:
1) The gauge is useless in sunlight......the bright sun makes the gauge unreadable.
2) The narrow gauge sensor has a very limited range, and the bars jump around quicky. The sensor can tell if the engine is at the desired economy setting of 14.7 pounds air to 1 pound of fuel - but beyond that it can only tell if the mixture is rich or lean. It cannot display a numeric value above or below 14.7.
3) With my current jetting the engine runs rich at most throttle settings - but I don't know how rich. I believe I am going to have to start with the main and drop jet sizes until it shows lean - then go back up one jet size. Then repeat this process for the needle and pilot jets.
4) Currently the engine runs lean at the throttle openings just before 1/4 open. As you gently accelerate away from a STOP and work up through the gears at a mild throttle setting - the engine is lean and you can feel the engine surging under the lean mixture. If you open the throttle anything more than 1/4 throttle it accelerates well and the O2 sensor moves out of the lean condition. When I last had the carb apart I set the float level at the lowest end of the range in the manual, as the bike has always started without the choke being on. I will raise the float a bit and see if that helps with the low speed lean condition.
Here are some pictures of the installed system. I used the Narrow Guage system that I had bought in 1997 when I used it to jet a car I was building - so I did not need to buy a new kit. I used High Temp black paint on the exhaust and I will let you know how it holds up. The silver spots are the Never Sieze that blew off the O2 sensor as it got hot.